|Class 11 Chemistry Redox Reactions||Types of Redox reactions|
Types of Redox reactions
i.e a + b --> ab (in this single product is formed).
For the reaction to be Redox, both the elements should be in elemental form.
For example: All combustion reactions are Redox reactions.
C0 + O2 --> CO2
Carbon Oxygen Carbondioxide
CuSO4 + Zn --> ZnSO4 + Cu
Copper Sulphate Zinc Zinc Sulphate Copper
Displacement reactions fit into two categories: metal displacement and non metal displacement.
Metal displacement: a metal in a compound can be displaced by another metal in the uncombined state .Metal displacement reactions find many applications in metallurgy. Few examples are:
Non-metal displacement: The non metal displacement involves mainly displacement of hydrogen and a rarely occurring reaction involving oxygen displacement .For example:
Non metal non-metal displacement: in this non metal gets displaced by non metal according to reactivities .For example if we consider fluorine and chlorine so, it is but obvious that fluorine can replace chlorine as it is more reactive.
H2O2 --> H2O + H2
Hydrogen Peroxide Water Oxygen Gas
In above example, the oxidation number of Oxygen which is -1 in peroxide increases to zero in O2 and decreases to -2 in water.
There are two types of Redox reactions
Direct Redox reaction: In which oxidation and reduction both occur in same beaker. In this electron so produced does not travel to large distance.
For example: A beaker containing Zinc rod dipped in Copper sulphate solution in this the following reaction occur:
Zn + CuSO4 --> ZnSO4 + Cu
Zinc CopperSulphate Zinc Sulphate Copper
In this zinc being more reactive displaces copper from copper sulphate and forms zinc sulphate and copper.
Indirect Redox reactions: In it oxidation and reduction occur in different beakers. The electron so produced has to travel a certain distance that leads to generation of current.
Example: Daniel cell: A cell containing Zn-Cu couple that we are going to study in detail now as given below but before that let us make you familiar with the general term used in redox reaction that is Redox couple.